Broadband data and video services have not been widely available to users on mobile platforms such as aircraft, boats, trains, and automobiles. Network systems have traditionally been limited in bandwidth and link capacity, making it prohibitively expensive and/or unacceptably slow to distribute such services to all passengers on a mobile platform. Certain limited services are available to provide video programming to a mobile platform. For example, one service provides either TV broadcast services from available direct broadcast signals (i.e. Echostar® and DirecTV®) or provides a custom TV broadcast signal through dedicated satellite links (i.e. Airshow®).
Limited Internet access also is currently available to a user on a mobile platform. For example, a narrow-bandwidth Internet connection is available via a standard computer telephone modem between a user's computer and the air-ground or ship-shore telephony system. Another service is anticipated to provide world-wide-web content to users on a mobile platform. The web content, however, is pre-stored on a server located on the mobile platform and is updated while the platform is in an inactive mode, for example, when an aircraft is parked at an airport gate or when a ship is docked at a port.
A system described in co-pending U.S. patent application Ser. No. 09/639,912 provides bi-directional data services and live television programming to mobile platforms. Data content is transferred via satellite communications link between a ground-based control segment and a mobile RF transceiver system carried on each mobile platform. Each user on each mobile platform is able, using a laptop, personal digital assistant (PDA) or other computing device, to interface with an on-board server. Each user can independently request and obtain, for example, Internet access, company intranet access and live television programming. Real-time programming is supplied, for example, by Direct Broadcast Satellite (DBS) service providers such as Echostar® and DirecTV®. The content is kept fresh by periodic updates from at least one ground-based server.
As on-board users make various requests for data content and network access while a mobile platform travels, it is necessary for the above system to determine how to transmit data content to the platform from the ground segment. More specifically, as a platform travels through a satellite coverage region, it intermittently initiates and terminates two-way communication links with the ground segment via satellite. Each time a two-way link is established between the ground segment and the platform, a data routing path to the platform must be discovered. That is, the above system must determine how to route data packets to the platform in such a way that data content is properly sequenced and reassembled when it reaches its destination. Additionally, when the moving platform terminates a two-way link with the ground segment, any such routing paths are allowed to expire from the system routing tables and thus are removed from the system to prevent attempts to transmit data via the terminated link. Therefore, each time a new two-way communication link is established with a mobile platform, the system must discover a new data routing path to the mobile platform before data content can be transmitted to the platform.
It is desirable to provide multiple data routing paths to a platform, in order to provide push services to the platform and to increase efficiency of data transfer through use of techniques such as statistical multiplexing. When a platform can establish links via more than one transponder, however, it becomes increasingly possible for the system to misroute data to expired or invalid paths.